Some conventional radio paging receivers have a function that when no reception of new message nor switching at operation part occurs during a given time period, the display image of liquid-crystal display can be turned off automatically to avoid consuming its battery by such a useless display image that its user does not need to look. This function is called "display auto-reset function". In a radio paging receiver with such a display auto-reset function, when there is no reception of a new message or a switching of an operation part occurs during a given time period after the radio paging receiver enters a waiting state, the display image of liquid-crystal display can be turned off automatically by the operation of the display auto-reset function.
However, for the conventional radio paging receivers with such a display auto-reset function, since even a display image that is needed can be turned off automatically by the operation of display auto-reset function, the user may be inconvenienced. Therefore, a radio paging receiver having a function that re-displays a display image automatically turned off by the operation of display auto-reset function has been also developed. For example, prior arts about such a function of radio paging receiver are described in Japanese patent application laid-open Nos. 02-190037 (1990) and 03-046833 (1991). In the former application prior art, the content of a message displayed just before the display image is turned off by the operation of display auto-reset function can be re-displayed by the key operation for re-displaying. In the latter application prior art, the content of a message displayed just before the display image is turned off by the operation of display auto-reset function can be re-displayed by the key operation for re-displaying to be conducted within a certain time period after the turn-off of the display image.
Also, though a user who uses less frequently such a radio paging receiver may feel convenient since a useless battery consumption can be cut down to save the life of battery when the display image is turned off automatically after a certain time period after displaying a message, a heavy user who has to operate frequently the switch to re-display a turned-off image to confirm a reception message not noticed and to confirm the reception time will feel inconvenient for the display auto-reset function that automatically turns off the display image after a certain time period after displaying a message. Therefore, many of conventional radio paging receivers with the display auto-reset function are designed such that the user can set selecting the turn-on or turn-off of the display auto-reset function mode where the display auto-reset function operates.
However, such a radio paging receiver capable of selecting the turn-on or turn-off of display auto-reset function mode cannot be always convenient to its user. For example, to a user who uses it frequently during the day but does not frequently use it at night, when selecting the turn-off of display auto-reset function mode in the morning, it can be convenient during the day since the display auto-reset function more is turned off, but it must be set again to select the turn-on of display auto-reset function mode at night when the frequency of use decreases. Thus, the user needs to set selecting the turn-on or turn-off of display auto-reset function mode in the morning and evening, every day.
Accordingly, the conventional radio paging receivers with the display auto-reset function fail to satisfy the requirements of all users.